The present disclosure relates generally to computers and more specifically to a partition boot record for a computer memory device that can change types dynamically, such as from a non-recognizable boot record to a recognizable boot record.
In a computer having one or more storage devices such as a hard disk drive, the storage devices are often separated into different partitions so that certain data or programs can be stored on separate partitions. For example, in a computer that utilizes a Microsoft DOS, Windows, or Windows 95 operating system, as provided by Microsoft Corporation of Redmond, Wash., a single computer hard drive may be partitioned into one partition which would contain the operating system code and another partition which would contain utility or maintenance type programs. For the remaining discussion, only DOS will be described for the sake of brevity and clarity, it being understood that DOS is representative of the above described operating systems as well as many other operating systems.
One example of such a utility or maintenance type program is an electronic break-the-seal ("EBTS") program. An EBTS program is often used to enforce a software license agreement for another program. To implement the EBTS program, a first partition is created as a utility partition and contains the EBTS program. A second partition is created as a primary partition and contains the program subject to the software license. Initially, the utility partition is marked as "active" so that the computer access the utility partition first. Upon acceptance of the license agreement, the primary partition is then marked as active so that the computer will subsequently access the primary partition first.
However, the above scenario has several problems associated therewith. For one, it may not be desirable to allow the user to access the utility partition during his normal operation of the computer. This may be because the user can access various maintenance and utility programs that are too powerful and would allow the user to easily lose the data on his hard drive, reconfigure the computer, or other scenarios best kept from the user. Therefore, a solution is to make the utility partition not normally visible by the operating system. This is accomplished by setting a "partition type code" for the utility partition to a value that is not recognizable by the operating system. The configuration and manipulation of storage devices such as a hard drive are described in the book THE HARD DISK SURVIVAL GUIDE by Mark Minasi, SYBEX, Inc., 1991, which is hereby incorporated by reference.
However, this introduces another problem. In the present example, the utility partition is initially marked as active so that when the computer boots, it looks only to the utility partition. While in the utility partition, the computer may want to run a maintenance or utility program such as the EBTS program. However, before the EBTS program can be run, the computer must first load operating system code from within the active partition. In the present example, the computer would load at least two DOS system files: IO.SYS and MSDOS.SYS. The IO.SYS system file checks the partition type code of the active partition to ensure that the partition type is one that it recognizes. Since this is not the case, the IO.SYS encounters an error and issues an error message, accordingly. As a result, the EBTS program can not be performed.